Crash Wall Design to Protect Mechanically Stabilized Earth Retaining Walls

Mechanically stabilized earth (MSE) retaining walls are used to provide roadway elevation for bridge approaches, underpass frontage roads, and other roadway elevation applications. Vehicular traffic may exist on the high (fill) side of the MSE retaining wall, the low side, or both sides. For traffic on the high side, a conventional traffic barrier might be placed on or near the top of the wall and mounted on a moment slab or a bridge deck. For traffic on the low side, a conventional traffic barrier might be installed adjacent to the wall or the wall itself may serve as the traffic barrier. Typical MSE wall panels are not designed to resist vehicle impacts. Therefore, structural damage to the wall panels and the earth fill would require complicated and expensive repairs. A simple reinforced-concrete crash wall constructed in front of the MSE wall panels could significantly reduce damage to the panels. It might prove practical to implement such a design to reduce costly repairs to the MSE wall structure. In this paper, LS-DYNA finite element analysis code was used to model and analyze a sacrificial crash wall design to determine its effectiveness in protecting an MSE retaining wall. Based on the LS-DYNA simulations, a crash wall that is 8 in. (0.2 m) thick is considered to be an adequate design to reduce damage to the MSE wall.